Abstract : In the last five years, environmentally-assisted cracking (EAC) has resurfaced as a service life-limiting factor for some gun system designs. In these EAC-affected system designs. mechanical loading factors alone do not appear to explain this loss of service life; chemical factors are also implicated. Using standard interior ballistic and nonideal gas-wall thermochemical analyses, the effect of EAC chemical factors is evaluated for three diverse generic gun systems encompassing the spectrum of gun system types. This study indicates that hydrogen-assisted cracking is the type of EAC responsible for such service life limitation. Results show that these hydrogen-producing and embrittling chemical factors include a major effect due to the addition of lubricants, a minor effect due to pressure oscillations, a subtle effect due to gaseous water-wall reactions. another subtle effect due to wall material choice, and nearly no effect due to gaseous acid-wall reactions.